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Journal Cover Reactive and Functional Polymers
  [SJR: 0.879]   [H-I: 62]   [5 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1381-5148
   Published by Elsevier Homepage  [2970 journals]
  • Dendrons with urea/malonamide linkages for gate insulators of n-channel
           organic thin film transistors
    • Abstract: Publication date: Available online 11 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Yu-Yi Hsu, Shih-Chieh Yeh, Shih-Hsun Lin, Chin-Ti Chen, Shih-Huang Tung, Ru-Jong Jeng
      A series of urea/malonamide dendritic molecules were prepared as gate insulators for organic thin film transistors (OTFTs). This series of molecules with different degrees of branching possess peripheral stearyl groups are dendrons generation 0.5 (G0.5), generation 1 (G1), generation 1.5 (G1.5), generation 2 (G2) and generation 2.5 (G2.5). In addition, two types of tetracarboxylic diimide derivatives, i.e. perylene diimide (PDI) and naphthalene diimide (NDI) with two different chain lengths of fluorinated alkyl end groups were prepared as semiconductors for OTFTs such as NDI-C4F7, NDI-C7F9, PDI-C4F7 and PDI-C7F9. The n-channel types of OTFTs were fabricated by spin-coating the gate insulators on Si/SiO2 substrates, and then depositing the semiconducting layers in vacuum without heating the substrate. Silver was used as contact electrodes for source and drain. The performance of OTFTs with dendrons as gate insulators were better than that of OTFTs modified by octadecyltrichlorosilane (ODTS). Moreover, the threshold voltages (V ths) of OTFTs shifted from positive voltage to negative voltage as the device was incorporated with higher generation of dendrons. This is because of different dielectric constants or surface energies between the interface of gate insulator and semiconducting layer. Among all samples in this study, the n-channel OTFT comprising PDI-C4F7 and G1.5 exhibited the best performance. In addition, an enhanced electron mobility and I on/I off ratio measured under ambient condition were 4.71×10−4 cm2 V−1 s−1 and 7.7×103, respectively. Apart from that, the influence of semiconducting molecular packing order on dendron gate insulator layers was investigated by grazing-incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM). Furthermore, pentacene-based p-channel OTFTs with G1.5 gate insulator also exhibited the highest performance. These OTFTs achieved 0.1cm2 V−1 s−1 and 6.3×104 for mobility (μ) and I on/I off ratio, respectively.


      PubDate: 2016-05-16T19:02:11Z
       
  • Covalent Biofunctionalization of Chitosan Nanofibers with Trypsin for High
           Enzyme Stability
    • Abstract: Publication date: Available online 12 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Jana Srbová, Marcela Slováková, Zuzana Křípalová, Monika Žárská, Martina Špačková, Denisa Stránská, Zuzana Bílková
      The electrospun chitosan nanofibers provide excellent material for immobilized proteolytic enzymes, and are biocompatible, nontoxic and hydrophilic matrices with large specific area. This paper deals with an application of electrospun chitosan nanofibers and optimizing conditions for their biofunctionalization by model proteolytic enzyme trypsin. Nanofibers from chitosan were prepared using NanospiderTM technology and covalent immobilization of trypsin followed. Three immobilization techniques preserving biocompatibility and utilizing amine and/or hydroxyl groups of chitosan were optimized and compared to simple adsorption to achieve maximum proteolytic activity per cm2 of the functionalized chitosan nanofibers (Tryp-NF). Significant differences were observed. Trypsin immobilized by the carbodiimide one-step protocol demonstrated the highest activity of the three procedures, ranging from 132 to 210IU/cm2 (i.e., 548–874IU/mg of nanofibers), depending on the initial amount of trypsin used. Long-term storage stability together with high reusability of Tryp-NF confirmed advantages of the immobilized enzyme. Tryp-NF showed no cytotoxicity toward growth of HeLa cells. The in vivo tests for irritation and skin sensitization demonstrated no undesirable skin reactions.


      PubDate: 2016-05-16T19:02:11Z
       
  • Synthesis of soluble polybenzimidazoles for high-temperature proton
           exchange membrane fuel cell (PEMFC) applications
    • Abstract: Publication date: Available online 7 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Jyh-Chien Chen, Ping-Yen Chen, Shih-Wei Lee, Geng-Luen Liou, Chun-Jung Chen, Yi-Hsin Lan, Kuei-Hsien Chen
      Three new diacids, 3, 5 and 7, were successfully synthesized by bromination, esterification, Suzuki coupling and hydrolysis from 4,4’-oxybis(benzoic acid). These diacids containing bulky bromide, phenyl and trifluoromethyl-substituted phenyl substituents, respectively. Polybenzimidazoles P1-P3, derived from these diacids and 3,3’-diaminobenzidine, were prepared in Eaton’s reagent at 145°C. They were soluble in NMP, DMAc and DMF. It indicates the effectiveness of introducing bulky substituents in improving the solubility of PBIs in polar aprotic solvents. P1-P3 also exhibited good thermal stability without significant degradation up to 400°C and high glass transition temperatures (>305°C). In addition, their oxidative stability, phosphoric acid doping levels, mechanical properties, dimensional stability after doping and proton conductivity were evaluated and compared with those of commercially available m-PBI. The proton conductivities of P1-P3 were in the range of 1.3-11.0×10−2 S/cm at 160°C. The fuel cells based on P2 containing phenyl substituents exhibited much better performance than the one based on m-PBI, with an open circuit voltage of 0.96 V and a peak power density of 781 mW/cm2 at 160°C.


      PubDate: 2016-05-10T18:54:30Z
       
  • Preparation and Application of Poly(AMPS-co-DVB) to Remove Rhodamine B
           from Aqueous Solutions
    • Abstract: Publication date: Available online 7 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Luanluan Zhang, Hejun Gao, Yunwen Liao
      A series of functional cross-linked polymer (Poly(AMPS-co-DVB)) were synthesized by 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and divinylbenzene (DVB). The physicochemical properties of the Poly(AMPS-co-DVB) were characterized by FT-IR, TGA, SEM, XRD, Zeta potential and UV–Vis. Those results showed that the Poly(AMPS-co-DVB) could provide mounts of adsorption sites from its special structure. The effects of the initial pH, dosage, contact time, and temperature on the adsorption of Rhodamine B (RhB) onto the Poly(AMPS-co-DVB) were investigated. It was found that the initial pH was an important factor for the molecules form of RhB and the surface formation of Poly(AMPS-co-DVB). With increasing of molar ratio of AMPS/DVB, the adsorption efficiency increased gradually. In the adsorption process, both physical and chemical mechanism is presence to adsorb RhB. The maximum adsorption capacity could get 407.9mg/g within 2h at room temperature.


      PubDate: 2016-05-10T18:54:30Z
       
  • New high-solubility aromatic polyesters with pendent phenothiazine:
           Synthesis, electrochromic and optoelectronic properties
    • Abstract: Publication date: Available online 9 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Xiaochuan Ma, Haijun Niu, Wanan Cai, Tiandi Xiao, Cheng Wang, Xuduo Bai, Yanhong Zhang, Wen Wang
      A series of aromatic polyesters were synthesized from dicarboxylic acids, containing pendent triphenylamine substituted with phenothiazine, and five different kinds of bisphenols. The aromatic polyesters exhibited good solubility in organic solvents due to bulky propeller-like triphenylamine and butterfly-like conformation of phenothiazine, which were convenient for the polymers to fabricate films and devices by spin- or inject-coating. They also revealed good thermal stability with 10% weight lost at 420°C. In addition, the polymer showed a strong yellow fluorescence at 522nm in the THF solution and irregular solvatochromic characteristic in polar solvents. Furthermore, their films had well reversible redox process in the range of 0–1.2V with the color changing from colorless neutral to red in the range of 0.80–0.85V. The calculated HOMO and LUMO energy levels of polyesters demonstrated their potential application as photoelectrical materials.


      PubDate: 2016-05-10T18:54:30Z
       
  • Modification of Eucalyptus and Spruce organosolv lignins with fatty acids
           to use as filler in PLA
    • Abstract: Publication date: Available online 9 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Oihana Gordobil, Itziar Egüés, Jalel Labidi
      Spruce (softwood) and Eucalyptus (hardwood) woods were used as raw material for lignin extraction by organosolv process. Chemical, structural and thermal characterizations of the extracted lignin samples have been performed using HPLC, GPC, FT-IR, 31P NMR, 13C NMR, DSC and TGA. Both lignins showed high purity, being Spruce lignin (OS) which presented the highest Klason lignin content (93%) and lowest sugar (0.5%) and sulphur (0.04%) content. Extracted lignin samples were chemically modified with dodecanoyl chloride fatty acid, in order to modify its thermal properties as glass transition temperature (Tg). The noticeable increase in the molecular weight and sharp decrease of Tg can be appreciated. Esterified lignins were used as filler in poly(lactic acid) (PLA) films elaborated by solvent casting in different concentrations (1, 5, 10, 25 and 50%). Mechanical, thermal and water barrier properties of prepared films were investigated. The results showed that the addition of both modified lignins contributed to greater ductility and lower stiffness, providing plasticity to PLA.


      PubDate: 2016-05-10T18:54:30Z
       
  • Comparison between two different click strategies to synthesize
           fluorescent nanogels for therapeutic applications
    • Abstract: Publication date: Available online 10 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Emanuele Mauri, Irene Moroni, Luca Magagnin, Maurizio Masi, Alessandro Sacchetti, Filippo Rossi
      The development of nanogels as nanoscale multifunctional polymer-based matrices for controlled drug and gene delivery purposes has been the subject of intense research during the last decades. Their use in biomedical field is related to the effect of their size on the interactions with living cells: only within a defined range nanoparticles could be subjected to active or passive cellular uptake. In this work we propose two methods to synthetize Rhodamine modified nanogels in order to produce nanostructures that could be traced during the cellular interactions and internalization and suitable as carrier for drugs or genes. We compared the obtained sizes and charges of both nanogels, underlining which one could be more useful for biological and therapeutic applications referring to the morphological and physico-chemical properties requested in accordance with medical needs. We also tested their cytocompatibility and their characteristic behavior as drug delivery vehicles.
      Graphical abstract image

      PubDate: 2016-05-10T18:54:30Z
       
  • A new route toward imidazoline-functionalized porous polymeric materials
           from corresponding polystyrene-polylactide diblock copolymers
    • Abstract: Publication date: Available online 10 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Joaquin Arredondo, Luis Ernesto Elizalde, Benjamin Le Droumaguet, Daniel Grande
      Novel imidazoline-functionalized diblock copolymers based on polystyrene (PS) and poly(D,L-lactide) (PLA) were synthesized as precursors to corresponding functional PS-based porous materials through a three-step sequential methodology starting from an asymmetric heterobifunctional initiator. α-Hydroxyl poly(4-cyanostyrene-co-styrene) random copolymers were first obtained via an atom transfer free-radical polymerization (ATRP) procedure by varying the amount of 4-cyanostyrene in the comonomer feed. Cyano groups were then transformed into corresponding imidazoline rings. Subsequently, the microwave-assisted ring-opening polymerization (ROP) of d,l-lactide from the imidazoline-functionalized PS-based macroinitiators allowed for the generation of semi-degradable diblock copolymers with different PLA volume fractions so as to develop microphase-separated morphologies. The precursors and resulting copolymers were analyzed by 1H, 13C NMR, and FT-IR spectroscopy. Upon induced shear-flow via channel-die processing, oriented materials constituted of PLA nanodomains in a polystyrene-based continuous matrix were formed. Hydrolysis in alkaline conditions of the PLA sacrificial block yielded imidazoline-functionalized porous PS-based matrices. The resulting porous frameworks were analyzed by scanning electron microscopy (SEM) and nitrogen sorption porosimetry.


      PubDate: 2016-05-10T18:54:30Z
       
  • Tetraphenylthiophene-terminated poly(acrylic acid) as pH- and bio-sensors
           by the aggregation-induced emission property
    • Abstract: Publication date: Available online 10 May 2016
      Source:Reactive and Functional Polymers
      Author(s): Deng-Jie Yang, Li-Yang Lin, Po-Chiao Huang, Jhen-Yan Gao, Jin-Long Hong
      Amphiphilic poly(acrylic acid) terminated with tetraphenylthiophene (TP) was prepared by atom transfer radical polymerization (ATRP) of t-butyl acrylate monomer, initiated by amino-functionalized TP, and the following by acid-catalyzed hydrolysis. With the hydrophobic TP terminal, a fluorophore with aggregation-induced emission (AIE) property, and the hydrophilic polymeric chain, the resulting polymer of TP-PAA is amphiphilic and self-assembled, through preferable hydrogen bond interactions among the carboxylic acid pedants, in water to form aggregates with strong AIE-related emission. The convenient dispersion of TP-PAA aggregates in water facilitated its applications as fluorescent sensor for pH value and for the natural protein of bovine serum albumin (BSA). Fluorescence variations in term of aggregation level of the TP terminals in different environments will be discussed in this study.


      PubDate: 2016-05-10T18:54:30Z
       
  • Fabrication of self-cross-linking fluorinated polyacrylate latex particles
           with core-shell structure and film properties
    • Abstract: Publication date: Available online 26 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Ting Lü, Dongming Qi, Dong Zhang, Qian Liu, Hongting Zhao
      A series of self-cross-linking fluorinated polyacrylate latex particles with core-shell structure were successfully prepared by one-step miniemulsion polymerization of methyl methacrylate (MMA), butyl acrylate (BA), dodecafluoroheptyl methacrylate (DFMA), and γ-methacryloxypropyl triisopropoxidesilane (MPS). The core-shell structure of the latex particles was confirmed and the latex films were characterized. Results showed that the latex films not only showed enhanced thermostability but also exhibited good hydrophobic property with the incorporation of a small amount of MPS (below 5wt% of monomers). This core-shell fluorine/silicone-containing polyacrylate latex could potentially be used for developing advanced multifunctional protective coatings such as antiwetting, anti-icing, antifogging, and anticorrosion.


      PubDate: 2016-04-29T18:48:56Z
       
  • Multifunctionality of self-assembled nanogels of curcumin-hyaluronic acid
           conjugates on inhibiting amyloid β-protein fibrillation and
           cytotoxicity
    • Abstract: Publication date: Available online 27 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Zhiqiang Jiang, Xiaoyan Dong, Hu Liu, Yongjian Wang, Lei Zhang, Yan Sun
      Aggregation of amyloid β-protein (Aβ) is a major pathological hallmark of Alzheimer's disease. Curcumin has been recognized as an inhibitor of Aβ aggregation, but its low water solubility and bioavailability limits its clinical applications. In this work, we conjugated curcumin to hyaluronic acid and drastically improved its solubility and stability. We found that the conjugates self-assembled into nanosized hydrogels that inhibited Aβ fibrillogenesis and mitigated the amyloid cytotoxicity more efficiently than free curcumin. More importantly, we found that there was an optimal curcumin substitution degree, at which the hydrogel exhibited the strongest inhibitory effect. Based on these findings, a mechanistic model was proposed. It suggested that besides the inhibitory effect of the conjugated curcumin, HA provided three synergistic functions. The first is that curcumin encapsulation into nanogels protected cells from the toxicity of free curcumin. The second was an isolation effect of the hydrogel network, which hindered the interactions between Aβ molecules. The third was the counteraction of the hydrophobic binding between Aβ and the conjugated curcumin against the electrostatic repulsion between the like-charged Aβ and HA. The two opposite forces could stretch the conformation of Aβ monomers, slowing down the aggregation and/or leading to off-pathway aggregations. This work offered new insights into the development of more potent nanoparticles for inhibiting Aβ fibrillogenesis and cytotoxicity.


      PubDate: 2016-04-29T18:48:56Z
       
  • Photoinduced detachment of cells adhered on 2-methacryloyloxyethyl
           phosphorylcholine polymer with cell binding molecule through
           photocleavable linkage
    • Abstract: Publication date: Available online 27 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Batzaya Byambaa, Tomohiro Konno, Kazuhiko Ishihara
      We prepared a novel substrate that its surface properties, e.g., cell adhesivity can be precisely and independently controlled by photoirradiation. The control of surface properties was achieved through an amphiphilic photoresponsive polymer; poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (BMA)-co-4-[4-(1-hydroxyethyl)-2-methoxy-5-nitrophenoxy]butyric acid (PL)) (PMB-PL). The PL unit can be cleaved into two parts via the external photoirradiation, which allows a successful detachment of cells adhered on the material surface. We immobilized epidermal growth factor (EGF) onto PMB-PL surface through a condensation reaction with carbonyl group on PL units to increase binding ability to specific cells. The EGF receptor overexpressed human skin epidermoid carcinoma epithelial cells (A431 cells) were used as a model cell line. The number of adhered cells was significantly increased on the EGF conjugated surface comparing to bare PMB-PL surface, although there was no cell attachment observed on poly(MPC-co-BMA) surface. The surface immobilized EGF also helped to enlarge the adherent areas of cell morphologies on surface, in contrast with an observation of round-shaped morphologies of adhered cells on bare PMB-PL surface. A simple photoirradiation procedure caused a successful detachment of adherent cells from the surface both PMB-PLs without and with immobilized EGF. The detached cells by photoirradiation were exhibited a very high cell viability and active proliferation rate as well as the non-irradiated control cells. Here, we demonstrated an easy way to immobilize biologically active molecules onto PMB-PL surfaces. We observed that immobilized bioactive molecules clearly affect the cellular morphologies and increase the efficiency of photoinduced detachment from the surface. We believe that the PMB-PL substrate can be a promising cell-collection platform for cell-based analysis through immobilized bioactive molecules, e.g., EGF that controls cellular behavior on 2D surface.


      PubDate: 2016-04-29T18:48:56Z
       
  • Comparing homogeneous and heterogeneous routes for ionic crosslinking of
           chitosan membranes
    • Abstract: Publication date: Available online 20 April 2016
      Source:Reactive and Functional Polymers
      Author(s): J.S. Marques, J.A.O.D. Chagas, J.L.C. Fonseca, M.R. Pereira
      H2SO4 — ionically crosslinked chitosan membranes were prepared via homogeneous and heterogeneous routes. The control variable in homogeneous crosslinking was the SO4 2−/NH3 + molar ratio (1:4 e 1:6) while for heterogeneous crosslinking it was the immersion time of pure chitosan membrane in H2SO4 0.5M aqueous solution (5 and 30min). FTIR-ATR suggested lower crosslinking degree for homogeneous crosslinking, corroborated by XRD analysis that indicated the maintenance of the crystalline structure for such membranes. Thermal analysis showed very similar degradation processes for homogeneous and pure chitosan but quite different for heterogeneous: not only in terms of degradation temperature but also in amount and signal of heat involved. Swelling index results were very dependent on pH of medium. Particularly in acidic medium, homogeneous crosslinked membranes, presented a higher swelling capacity than the heterogeneous ones. Mechanical properties revealed that both methodologies render membranes with lower tensile strength and elongation but with Young modulus about four times higher, due to the interactions of SO4 2− groups of H2SO4 with NH3 + of chitosan. Finally, AFM images showed dramatic changes on surface topology, with reduction of roughness for heterogeneous and an increase for the homogeneous one.


      PubDate: 2016-04-24T18:47:28Z
       
  • Ring expansion-controlled radical polymerization: Synthesis of cyclic
           polymers and ring component quantification based on SEC–MALS
           analysis
    • Abstract: Publication date: Available online 20 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Atsushi Narumi, Shuhei Hasegawa, Ryo Yanagisawa, Miho Tomiyama, Masatsugu Yamada, Wolfgang H. Binder, Moriya Kikuchi, Seigou Kawaguchi
      We report a ring expansion vinyl polymerization producing cyclic polymers using a tetra(oxyethylene) (TOE)-tethered cyclic initiator for the nitroxide-mediated controlled radical polymerization (NMP). Styrene (St) was polymerized with the cyclic NMP initiator 1 in the bulk to produce polymer 2. Structural analyses of 2 were performed by a size exclusion chromatograph equipped with a multiangle laser light scattering (SEC–MALS) detector, focusing on the relationships between the z-averaged root-mean-square radii of gyration (〈S 2〉z 1/2) versus the molecular weights. The results proved that 2 would consist of ring components as a result of the ring expansion polymerizations and radical ring crossover reactions together with ring-opened linear components, in which the amount of ring components increased with the increasing molecular weights. The data also enabled the quantification that approximately 13–40wt% of the final polymer 2 could be identified as the ring species in the M w range of 1×105–5×105 gmol−1.


      PubDate: 2016-04-24T18:47:28Z
       
  • DMAP-based flexible polymer networks formed via Heck coupling as efficient
           heterogeneous organocatalysts
    • Abstract: Publication date: Available online 22 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Wei Xu, Wu Xia, Yukun Guan, Yiming Wang, Cuifen Lu, Guichun Yang, Junqi Nie, Zuxing Chen
      Two DMAP-based flexible polymer networks TPB-DMAP and TPA-DMAP have been successfully synthesized via palladium catalyzed Heck cross-coupling. The structures of these polymers were confirmed by solid state 13C CP/MAS and Fourier transform infrared spectroscopy (FTIR). Although both polymers have negligible surface areas, they exhibit excellent catalytic efficiency for the acylation of 1-phenylethanol with acetic anhydride due to their good swelling capacities. Utilized as a typical catalyst, the polymer TPA-DMAP shows high activities for acylation of a variety of alcohols to the corresponding esters. Moreover, the catalyst can be recycled at least ten times without obvious loss of catalytic activity.


      PubDate: 2016-04-24T18:47:28Z
       
  • Hydration of ion exchangers: thermodynamics and quantum chemistry
           calculations. II an improved variant of the predominant hydrates model
    • Abstract: Publication date: May 2016
      Source:Reactive and Functional Polymers, Volume 102
      Author(s): Vladimir Soldatov, Vladimir Zelenkovskii, Eugeny Kosandrovich
      Valuable information on the state of water molecules in the ion exchanger can be obtained by joint application of thermodynamic and quantum chemistry methods to treatment of water sorption isotherms. An improved variant of the Predominant Hydrates model accounts for competitive process of formation in the resin of several hydrates forming an ideal mixture with the free water. The parameters of the model are number of hydrates, number of water molecules in each hydrate and Gibbs energies of the hydrates formation. The first two parameters can be obtained from quantum chemical calculation of structure of the molecular model of swollen ion exchanger and the energy state of the water molecules. The new approach was illustrated by its application to experimental data of Gregor H.P., Sundheim B.R., Held K.M., Waxman M.H. Studies on ion-exchange resins. V. Water vapor sorption, J. of Coll. Sci., 7: 5 (1952) 511–534 on isopiestic data of water sorption by Li+ and Na+ forms of sulfostyrene resin with 10% DVB. The experimental water sorption isotherms can be accurately described by the model accounting for the presence in the resin of two hydrates with the same number of water molecules for Li+ and Na+ forms. The difference in the intensity of hydration reveals in the different Gibbs energy of the hydrates formation. The mole fraction of water in different hydrates and the free water was calculated. It appeared that more than a half of water molecules in both cases are free and enter the resin phase due to the entropy increase upon distribution of the free water between the solution and the resin.


      PubDate: 2016-04-19T07:53:01Z
       
  • Synthesis and application of photo-active carboxymethyl cellulose
           derivatives
    • Abstract: Publication date: May 2016
      Source:Reactive and Functional Polymers, Volume 102
      Author(s): M. Monier, D.A. Abdel-Latif, H.F. Ji
      In this work, the polysaccharide carboxymethyl cellulose (CMC) was first activated via periodate oxidation then modified by insertion of photo-active cinnamic acid hydrazide moieties to finally produce the photo-crosslinkable CMC-CM with various extents of functionalizations. The chemical structures of the manufactured polymeric materials were entirely investigated utilizing FTIR, 1H, 13C NMR, and UV–vis spectra. Upon irradiation in UV light, the progress and kinetics of the cross-linking were detected using UV–vis spectra. Moreover, the crystallinity changes before and after chemical modification and subsequent UV irradiation were examined by XRD spectra. Also, the obtained hydrogels with various cross-linking densities were freeze dried to visualize the morphological changes using SEM. In addition, the rheological experiments indicated the improvement of the hydrogel mechanical properties by increasing both UV irradiation time and degree of cinnamate functionalization. The obtained hydrogel exhibited good swelling, gelation and biodegradation properties, which indicate a promising potential in different biomedical applications.


      PubDate: 2016-04-19T07:53:01Z
       
  • Editorial Board
    • Abstract: Publication date: May 2016
      Source:Reactive and Functional Polymers, Volume 102




      PubDate: 2016-04-19T07:53:01Z
       
  • High performance polymer nanocomposites for additive manufacturing
           applications
    • Abstract: Publication date: Available online 19 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Al C. de Leon, Qiyi Chen, Napolabel B. Palaganas, Jerome O. Palaganas, Jill Manapat, Rigoberto C. Advincula
      Additive manufacturing (or 3D printing) involves the process of fabricating a part by layer-by-layer assembly of materials with processes such as extrusion, binding, melting, and photopolymerization. It is transforming how we assemble our prototypes and, in the future, manufacture our products. There have been a number of materials that can be utilized for this technology, however, high performance polymer nanocomposites are a very important class of material that is just recently being used in additive manufacturing. High performance polymer is a group of polymer materials that are known to retain its desirable mechanical, thermal, and chemical properties when subjected to harsh environment such as high temperature, high pressure, and corrosive chemicals. When mixed with nanofillers such as carbon nanotube, nanoclay, and graphene, these polymers can have improved mechanical properties and sometimes acquire properties that were not present initially like thermal and electrical conductivity. This review article aims to summarize available additive manufacturing techniques, high performance polymers and nanofillers available, and research efforts on its use for additive manufacturing.


      PubDate: 2016-04-19T07:53:01Z
       
  • Modification of stress-strain behaviour in aromatic polybenzoxazines using
           core shell rubbers
    • Abstract: Publication date: Available online 14 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Elliot Douse, Sotirios Kopsidas, David Jesson, Ian Hamerton
      2,2-Bis(3,4-dihydro-3-phenyl-2H-1,3-benzoxazine)propane (BA-a) is blended with a commercial core shell rubber (CSR), Genioperl P52, based on a siloxane core and an acrylic shell, at a range of loadings (1–32wt.%). Scanning electron microscopy and energy-dispersive X-ray analysis reveals an even distribution with good cohesion between the resin and CSR particles. Measurements carried out by dynamic mechanical analysis and thermogravimetric analysis show modest improvements in glass transition temperature (3%) and significant enhancement of thermal stability (20%) when CSR (32wt.%) was incorporated. Such improvements are linearly related to CSR content. Moderate reductions in modulus (30%) were observed with the highest (32wt.%) loadings of CSR and were also linearly proportional to CSR content. Thermal analysis demonstrated a small inhibitory effect, with activation energy raised by 4% with the blend containing 32wt.% CSR and 3% in the blend containing 8wt.% CSR. It was found that mechanical stirring of the CSR particles into the molten BA-a monomer was the most practical solution for dispersion and effectively broke down CSR agglomerates in the bulk and produced void free samples upon curing, although some minor defects were apparent with higher loadings of core shell rubber. Four batches of dog bone specimens (containing 0, 8, 16 and 32wt.% CSR) were manufactured and underwent tensile testing. An average increase in extension was observed from 0.82mm for the pristine poly(BA-a), to 1.14mm (32wt.% CSR) was achieved. The introduction of CSR has a deleterious impact on tensile strength (24.67MPa, pristine poly(BA-a) compared with 20.48MPa containing 32wt.% CSR; Young's modulus of 5.4GPa for pristine poly(BA-a) compared with 3.1GPa containing 32wt.% CSR). Following tensile tests, scanning electron microscopy reveals rubber cavitation as the principal toughening mechanism.
      Graphical abstract image

      PubDate: 2016-04-15T07:46:09Z
       
  • Ultra-fine silver nanoparticles dispersed in mono-dispersed amino
           functionalized poly glycidyl methacrylate based microspheres as an
           effective anti-bacterial agent
    • Abstract: Publication date: Available online 14 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Yuanming Deng, Jiefeng Li, Yitao Pu, Yuemei Chen, Jinlai Zhao, Jiaoning Tang
      In this study, amino functionalized poly glycidyl methacrylate (am-PGMA) based microspheres prepared via soap-free emulsion polymerization were served as polymeric matrices for silver nanoparticles (Ag NPs) loading and applied as anti-bacterial agent. The amino and hydroxyl enriched am-PGMA based microspheres served as both matrix for Ag+ absorbance through coordination bond and reduce agent under hydrothermal condition in a high-pressure steam sterilization. The effects of chemical structure of microspheres on the morphology of Ag NPs/polymer composites were investigated. Am-PGMA/Ag composite spheres with ultra-fine Ag NPs up to 26wt% were well characterized and their antibacterial activity were studied and discussed in detail. It was found that the Ag NPs loading in microspheres showed comparable anti-bacteria activities in terms of Ag with the minimum inhibitory concentration (MIC) low to 20 and 20mg/L (equal to 5.2, 5.2mg/L Ag) for Escherichia coli and Staphylococcus aureus respectively. The obtained composites spheres (am-PGMA/Ag) are promising alternative anti-bacterial agents in industrial and biomedical applications.


      PubDate: 2016-04-15T07:46:09Z
       
  • Negatively charged hydrophobic nanoparticles inhibit amyloid
           β-protein fibrillation: The presence of an optimal charge density
    • Abstract: Publication date: Available online 9 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Hongchen Liu, Baolong Xie, Xiaoyan Dong, Lei Zhang, Yongjian Wang, Fufeng Liu, Yan Sun
      Self-assembly of amyloid β-protein (Aβ) is closely related to the pathogenesis of Alzheimer's disease (AD). Many studies suggest that polymeric nanoparticles (NPs) can inhibit Aβ fibrillogenesis depending on their electrostatic and hydrophobic properties, but the underlying molecular mechanism remains unknown. Herein, the inhibitory effect of NPs with equivalent content of hydrophobic groups but different surface negative charge densities on Aβ fibrillogenesis is examined. Firstly, the polymeric NPs of similar sizes were synthesized by copolymerizing equal proportion of N-isopropylacrylamide and different proportion of N-t-butylacrylamide and acrylic acid. Then, the inhibitory effects of these NPs on Aβ42 fibrillization and the corresponding cytotoxicity were investigated using thioflavin T fluorescent assay, transmission electron microscopy, dynamic light scattering analysis, and cell viability assay. It was found that these NPs showed remarkable inhibitory capability against Aβ42 fibrillogenesis and alleviated its cytotoxicity. The inhibitory capability significantly depended on the capacity of the negative surface charges carried by NPs with an increase-decrease trend. The best inhibitory efficiency was obtained at an optimal surface negative charge density. Based on the findings, a mechanistic model was proposed by considering the two interactions between Aβ42 and NPs, namely, hydrophobic binding and electrostatic repulsion. The model suggested that at an appropriate negative charge capacity, the two opposite forces could be well-balanced, and thus led to the stretching of Aβ42 molecules instead of the formation of a harmful β-sheet structure. The polymeric NPs of well-designed surface of proper hydrophobicity and negative charge density could thus significantly slow down the Aβ42 fibrillation and/or result in an off-pathway aggregation with reduced cytotoxicity.


      PubDate: 2016-04-15T07:46:09Z
       
  • Melamine-based dendronized magnetic polymer in the adsorption of
           Pb(ΙΙ) and preconcentration of rhodamine B
    • Abstract: Publication date: Available online 10 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Mostafa Hossein Beyki, Farzaneh Feizi, Farzaneh Shemirani
      In this research, magnetic BaFe2O4 nanoparticles (NPs) have been synthesized via the sol-combustion process using triethanolamine as fuel. Thereinafter, the silica coated NPs have been reacted with carbon disulfide and melamine to prepare magnetic polytriazine-thiourea dendronized nanohybrid. Prepared materials have been characterized by XRD, FT–IR, VSM, EDX, TGA, BET and FE–SEM techniques. In view of potential application, the nanohybrid was employed for rhodamine B (RB) preconcentration as well as Pb(II) adsorption from aqueous solutions. Results showed that equilibrium time for both analytes obtained within 5min as RB and lead adsorption followed second order adsorption mechanism. Moreover, adsorption process followed the Freundlich isotherm model for the target analytes. Adsorbed RB and lead have been released from the sorbent surface with ethanol and HNO3 solution (0.1molL−1), respectively. Moreover, the sorbent showed good reusability after 5cycles of sorption and desorption.


      PubDate: 2016-04-15T07:46:09Z
       
  • Effect of poly(ε-caprolactone) as plasticizer on the properties of
           composites based on polylactide during hydrolytic degradation
    • Abstract: Publication date: Available online 11 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Ewa Olewnik-Kruszkowska, Patrycja Kasperska, Izabela Koter
      The aim of this work was to determine the impact the plasticizing agent has got on hydrolytic degradation of polylactide-based composites in the form of films. The research involved polylactide composites where Nanofil2 or Montmorillonite K10 were used as nanoclays and (poly(ε-caprolactone)) was introduced into the polymer matrix as plasticizer. Hydrolysis was carried out in phosphate buffer solution (pH7.40) at 37°C. Degradation process of polylactide-based composites was studied by incubating samples in 100ml solution for a maximum of 180days. In order to determine the influence of the plasticizer on hydrolysis, the materials were investigated by various analytical techniques. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were used in order to investigate the thermal properties of samples during the degradation process. Gel permeation chromatography (GPC) was used to observe the decomposition of the polyesters. Morphology and structural changes during controlled hydrolysis were studied by atomic force microscopy (AFM). The results suggest that introduction of plasticizer into pure polymer as well as into PLA-montmorillonite system accelerates decompositions of investigated materials.


      PubDate: 2016-04-15T07:46:09Z
       
  • Physicochemical characterisation of hawthorn pectins and their performing
           in stabilising oil-in-water emulsions
    • Abstract: Publication date: June 2016
      Source:Reactive and Functional Polymers, Volume 103
      Author(s): J.C. Cuevas-Bernardino, C. Lobato-Calleros, A. Román-Guerrero, J. Alvarez-Ramirez, E.J. Vernon-Carter
      The physicochemical characteristics, intrinsic viscosity, adsorption dynamics and emulsifying properties of two hawthorn accessions pectins (HP50 and HP55) were evaluated and compared to those obtained for commercial citrus pectin (CP). Mark-Houwink-Kuhn-Sakurada coefficients, a MHKS =0.71±0.02 and k MHKS =5.08×10−3 ±2×10−4 gdL−1 were obtained from intrinsic viscosity data. The diffusion (K diff ), penetration (K 1) and the rearrangement (K 2) constants were determined from adsorption dynamics data of the pectins at the canola oil-water interface. K diff was higher and K 1 was lower for HP50 than for HP55 and for CP. These results had bearing on the stability of oil-in-water emulsions. Higher K diff produced smaller initial droplet sizes, due to the faster diffusion of molecules to the interface, while lower K 1 produced longer-term stability, as a more consolidated and stronger interfacial film was formed faster, making arduous the penetration of newly arriving molecules through the monolayer. The rate of creaming was lower the smaller was the initial droplet size and the higher the apparent viscosity of the emulsions.


      PubDate: 2016-04-15T07:46:09Z
       
  • Preparation and characterization of porous scaffolds from
           chitosan-collagen-gelatin composite
    • Abstract: Publication date: Available online 14 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Robert Tylingo, Grzegorz Gorczyca, Szymon Mania, Piotr Szweda, Sławomir Milewski
      Novel porous scaffolds composed of chitosan, collagen and gelatin were prepared and characterized. For preparing scaffolds gelatin and collagen isolated from fish skins with various physicochemical properties were used. In order to reduce preparation solubility glutaraldehyde in the amount of 1%, w/w relative to the total biopolymers weight in solution was used. All obtained biomaterials showed a homogeneous porosity. Protein polymer type determined the rheology and mechanical properties of obtaining preparations. The use of protein polymers decreased swelling capacity of materials approximately 30% compared to the materials obtained from chitosan. Materials containing gelatin showed the highest solubility (approx. 30%). Scaffolds obtained in 100% of chitosan proved to be harder than collagen materials an average of 30% and less flexible more than twice. In relation to the gelatin materials were characterized by smaller values of both measured parameters on average 40% and 30% respectively. Materials containing protein polymers showed good antioxidant properties.


      PubDate: 2016-04-15T07:46:09Z
       
  • Porous polyimide framework: A novel versatile adsorbent for highly
           efficient removals of azo dye and antibiotic
    • Abstract: Publication date: Available online 6 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Yan Wang, Qiang Gao, Qingliang You, Guiying Liao, Hua Xia, Dongsheng Wang
      Porous organic frameworks (POFs) have aroused considerable interest owe to its high surface areas, superior chemical and thermal stabilities, good mechanical and abundant porosity. In this study, a porous polyimide (PI) with abundant amine groups was synthesized by the reaction of melamine and pyromellitic dianhydride. And its versatile adsorption performance towards organic pollutants, including azo dye (methyl orange (MO)) and antibiotic (tetracycline (TC)) was investigated. The PI was characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA), and N2 adsorption-desorption techniques. The obtained product possessed high thermal stability and exhibited a high surface area (635.5m2·g−1) and a large pore volume (0.98cm3·g−1). The pH effect study showed that MO adsorption was highly pH-dependent with an optimal pH3, while the TC adsorption was effective in the pH range of 6–8. Batch adsorption experiments were carried out to study adsorption kinetics and adsorption thermodynamics. The result showed that the kinetics experimental data were fitted to pseudo-second-order kinetics model better, and adsorption isotherm could be described by the Langmuir isotherm model perfectly. The maximum adsorption capacities calculated from the Langmuir isotherm model are 609.8 and 155.8mg/g at 318K for MO and TC, respectively. The thermodynamic study showed that the adsorptions of TC and MO on PI were spontaneous (ΔG <0) and endothermic (ΔH >0). Findings in this study demonstrated that the porous PI should be a powerful adsorbent in organic pollutants removal.


      PubDate: 2016-04-09T06:00:15Z
       
  • Quantitative determination of acidic groups in functionalized graphene by
           direct titration
    • Abstract: Publication date: Available online 6 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Jakub Ederer, Pavel Janoš, Petra Ecorchard, Václav Štengl, Zuzana Bělčická, Martin Šťastný, Ognen Pop-Georgievski, Vlastimil Dohnal
      Direct titration with NaOH was used to quantify the acidic functional group content in graphene oxide (GO). Three different methods were used to evaluate the experimental data: the first derivation of the titration curve, Gran linearization and an empirical approach suggested by Ritchie and Perdue for the evaluation of the titration data for humic substances. Two types of acidic functional groups were identified and classified, more or less arbitrarily, as being either carboxylic or phenolic. Typically, the carboxylic acid group contents ranged from ca. 0.80 to 1.70mmol/g, except for the carboxylated GO prepared by the reaction with chloroacetic acid, which contained significantly more carboxylic acid groups. The titration results are consistent with those obtained by instrumental methods such as X-ray diffraction (XRD), infrared spectroscopy (IR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). For modelling purposes (proton binding and metal binding), a bimodal continuous distribution model was proposed, and its parameters were estimated from the titration data.


      PubDate: 2016-04-09T06:00:15Z
       
  • Facile synthesis of amphiphilic poly(ethylene glycol) conjugate and its
           micellization as injectable targeted vehicle for DOX
    • Abstract: Publication date: Available online 7 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Jin Zeng, Peng Liu
      Amphiphilic FA-PEG2000-OA conjugate was designed, comprising hydrophilic poly(ethylene glycol) (PEG), with a folate targeting moiety and a biodegradable hydrophobic oleic acid (OA) segment at each chain ends. The near-monodisperse flower-shaped folate-functionalized micelles were self-assembled in aqueous solution for the folate receptor (FR)-mediated targeted delivery of the anticancer drug (doxorubicin (DOX)) to cancer cells. The drug loading and in vitro pH responsive controlled release performance revealed that the FA-PEG2000-OA micelles had potential application as drug delivery systems (DDS) for hydrophobic anthracycline anti-cancer drugs such as DOX. With the aid of FA-PEG2000-OA micelles as DDS, which was non-cytotoxic in low concentrations, the cancer cell-killing ability of DOX has been obviously enhanced, demonstrating their promising applications to overcome multi-drug resistance (MDR) in tumor treatments.


      PubDate: 2016-04-09T06:00:15Z
       
  • Preparation of a thermosensitive fiber and its carbon dioxide
           adsorption/desorption properties
    • Abstract: Publication date: Available online 9 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Yu Wang, Fengqin Yin, Shuixia Chen, Xiaotong Peng
      A thermosensitive fiber (VF-NIPAAM-co-AM) was developed by grafting N-isopropylacrylamide (NIPAAM) and acrylamide (AM) onto the surface of viscose fiber (VF) through the simultaneous grafting copolymerization approach. The grafted fiber was subsequently aminated with triethylenetetramine (TETA) to prepare a solid amine adsorbent for CO2 capture. The effect of NIPAAM/AM molar ratio on the thermosensitive properties of the grafted fiber was investigated. It was found that the contact angle of VF-NIPAAM-co-AM increased with the increasing of NIPAAM/AM molar ratio. For all the prepared fibers, the contact angle of VF-NIPAAM-co-AM at 343K was higher than that at 293K, indicating the thermosensitive property of the grafted copolymer fibers. After amination, the contact angle of VF-NIPAAM-co-AM-TETA at 293K and 343K were 79.86°and 84.14°, respectively. Even though the contact angles of aminated fibers decreased, the fiber still retained a certain thermosensitive property. Studies on the adsorption and desorption behaviors of VF-NIPAAM-co-AM-TETA and VF-AM-TETA indicated that CO2 could be more efficiently and completely desorbed from VF-NIPAAM-co-AM-TETA at 80°C than from VF-AM-TETA, a structurally similar fiber but without NIPAAM.


      PubDate: 2016-04-09T06:00:15Z
       
  • Synthesis and photophysical study of some new highly thermostable blue
           
    • Abstract: Publication date: Available online 2 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Corneliu Hamciuc, Mihaela Homocianu, Elena Hamciuc, Ionela-Daniela Carja
      New poly(1,3,4-oxadiazole-imide)s were synthesized from a diamine containing 1,3,4-oxadiazole ring, 4.4′-diamino-4″-[(2-(4-phenoxy)-5-(4-dimethylaminophenyl)-1,3,4-oxadiazole]triphenylmethane, and different aromatic dianhydrides: 4.4′-(hexafluoroisopropylidene)diphthalic anhydride, 9.9-bis[(3.4-dicarboxyphenoxy)phenyl]fluorene dianhydride, 4.4′-(4.4′-isopropylidenediphenoxy)bis(phthalic anhydride) and perylene-3,4,9,10-tetracarboxylic dianhydride. The polymers were easily soluble in polar organic solvents and exhibited high thermal stability, having 5% weight loss in the range of 445–470°C and glass transition temperature in the domain of 201–244°C. The optical properties were investigated in different media. The absorption characteristics (intensity, absorption maximum and shape) of investigated compounds depended on their chemical structures and the nature of environment. The emission of these samples was represented by one broadened and blue emission band. The largest and solvent dependent Stokes shifts values were obtained. The fluorescence quantum yield (QY) values of polymer with hexafluoroisopropylidene groups, in tetrahydrofuran solution, depended on the wavelength used for excitation. This is an exception from Kasha's rule and Vavilov's law, which was attributed either to photodecomposition or to the enhancement of intramolecular energy transfer process competing with internal conversion between singlet states. High QY values were obtained for polymers with isopropylidene or fluorene units in dimethyl sulfoxide (polar solvent), which may be due to the strong overlap of electronic transitions of species from system.


      PubDate: 2016-04-06T02:28:04Z
       
  • Experimental and theoretical study of molecular interactions between
           2-vinyl pyridine and acidic pharmaceuticals used as multi-template
           molecules in molecularly imprinted polymer
    • Abstract: Publication date: Available online 2 April 2016
      Source:Reactive and Functional Polymers
      Author(s): Lawrence Mzukisi Madikizela, Phumlani Selby Mdluli, Luke Chimuka
      Molecular interactions between functional monomer and template molecules are regarded as the driving force for the success of a molecularly imprinted polymer. In this study, a multi-template molecularly imprinted polymer (MIP) for ibuprofen, naproxen and diclofenac was synthesized in an oil bath set at 70 °C for 24 hours. 2-vinyl pyridine, ethylene glycol dimethacrylate, toluene and 1,1’-azobis-(cyclohexanecarbonitrile) were used as functional monomer, cross-linker, porogen and radical initiator, respectively. A non-imprinted polymer (NIP) was synthesized using a similar approach with the omission of templates. Monomer-template interactions were examined using Molecular Dynamics and Fourier Transform Infrared Spectroscopy (FTIR). Both molecular dynamics and FT-IR results indicated the formation of the hydrogen bond between the templates and 2-vinyl pyridine. Molecular dynamics further revealed the identity of the hydrogen atoms in the templates involved in interactions with nitrogen atom on the functional monomer in the presence of toluene molecules. Surface area obtained for the MIP using Brunauer, Emmett and Teller method was 282 m2/g, whereas 232 m2/g was obtained for the NIP. This indicated that MIP has more binding sites compared to the NIP. Furthermore, batch adsorption and selectivity experiments were carried out in the presence of gemfibrozil as the competitor. When such experiments were carried out in toluene, the adsorption capacities (mg/g) obtained for naproxen, ibuprofen, diclofenac and gemfibrozil were 14.4, 11.0, 14.0 and 7.5, respectively. These results show that the MIP was more selective to the compounds that were used as template molecules.
      Graphical abstract image

      PubDate: 2016-04-06T02:28:04Z
       
  • Electrophoretic detection of alginate by Hematoxylin and Eosin
           fluorescence: Implications in cell encapsulation/tissue engineering
    • Abstract: Publication date: Available online 28 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Yogesh Kumar Verma, Rajendra Prashad Tripathi, Gurudutta Ugraiah Gangenahalli
      Alginate is a biocompatible polymer commonly used for cell encapsulation and synthesis of biomaterials in pure or modified form. In this study we have developed a fluorescence based method to visualize Hematoxylin and Eosin (H&E) stained alginate (pure/protein modified) by electrophoresing it in agarose gel, followed by its UV exposure. The shift in the migration pattern of H&E stain indicates presence of alginate, whereas the conjugated protein (fibronectin) could be detected by UV spectroscopy. H&E stain was found to specifically and permanently stain alginate and the fluorescence and migration pattern of H&E was not affected in the presence of other dye (Rhodamine β Isothiocyanate - RBITC) conjugated to alginate. We found that the presence of all the ingredients of H&E is mandatory to influence the migration pattern of this dye (bound to alginate) upon agarose gel electrophoresis. The main advantage of this method is that it is cheaper and faster than the other methods for alginate visualization and can be accomplished with standard lab chemicals and equipment.


      PubDate: 2016-04-01T02:21:15Z
       
  • Bioinspired double-positively charged phosphodicholine-chitosan and
           zwitterionic phosphorylcholine-chitosan conjugates: The associated water
           structure, biocompatibility and antibacterial action
    • Abstract: Publication date: Available online 24 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Zhaoyu Cao, Minming Wu, Yunfei Zhao, Lisha Dai, Rong Zeng, Mei Tu, Jianhao Zhao
      Bioinspired double-positively charged phosphodicholine (PdC)-chitosan conjugate was synthesized via Atherton-Todd reaction, which can hydrolyze to zwitterionic phosphorylcholine (PC)-chitosan in basic solutions, confirmed by 1H and 31P NMR spectra. Thermal analysis revealed that there existed the freezing bound water due to the introduction of PdC and PC groups for both PdC-chitosan and PC-chitosan, implying that double-positively charged PdC-chitosan may exhibit excellent biocompatibility as zwitterionic PC-chitosan. Cytotoxicity, hemolysis and antibacterial activity evidenced that PdC-chitosan displayed high antibacterial activity against Escherichia coli and Staphylococcus aureus under physiological conditions, and very low cytotoxicity and hemolytic activity, owing to its highly selective lysis of bacterial membranes over mammalian cell membranes mainly resulting from the competition of electrostatic interactions and shielding effect of the restrained water of PdC, while biocompatible PC-chitosan showed no antibacterial activity due to its non-fouling property. The results indicated that biocompatible double-positively charged PdC-containing bioinspired polymers may provide a promising approach for developing safe and effective antibacterial agents.


      PubDate: 2016-03-27T14:36:47Z
       
  • Biocatalytic protein membranes fabricated by electrospinning
    • Abstract: Publication date: Available online 25 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Gözde Kabay, Gizem Kaleli, Zahida Sultanova, Tolga Tarkan Ölmez, Urartu Özgür Şafak Şeker, Mehmet Mutlu
      In this study, a protein-based catalytic membrane was produced by electrospinning. Membrane activity was characterised in terms of response current for various glucose concentrations. We focused on the preparation of a scaffold by converting a globular protein to other structural forms using catastrophic solvents. A scaffolding protein, bovine serum albumin, and an enzyme, glucose oxidase (GOD), were selected as a model natural carrier matrix and a biologically active agent, respectively. Beta-mercaptoethanol (β-ME) was used to convert the globular protein to an amyloid-like form. A structural stabilising agent, 2,2,2-triflouroethanol (TFE), was used to maintain the final α-helical structure of the amyloid-like protein. The TFE:PBS (phosphate-buffered saline) ratio and various electrospinning parameters were analysed to minimise activity loss. Using this approach, we applied electrospinning to an active enzyme to obtain biocatalytic nanofibrous membranes. After optimising the protein electrospinning process, the activities of the protein nanofibrous membranes were monitored. GOD remained active in the new membrane structure. The highest enzyme activity was observed for the membranes prepared with a 1.5:1 (v:v) TFE:PBS solvent ratio. In that particular case, the immobilized enzyme created a current of 0.7μA and the apparent activity was 2547±132U/m2.


      PubDate: 2016-03-27T14:36:47Z
       
  • An effective β-cyclodextrin polyurethane spherical adsorbent for the
           chromatographic enrichment of corilagin from Phyllanthus niruri L. extract
           
    • Abstract: Publication date: Available online 26 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Jun Zhao, Tian-Tian Liu, Guo Chen
      A novel β-cyclodextrin polyurethane (β-CD-PU) spherical adsorbent was prepared by the reversed-phase suspension crosslinking technique for the chromatographic enrichment of a polyphenolic compound corilagin. β-Cyclodextrin (β-CD) and PEG1000 were co-crosslinked with hexamethylene diisocyanate, and the polyurethane skeleton was formed and confirmed by FTIR, TGA and 13C CP/MAS NMR analysis. A chromatographic operation was carried out with the raw Phyllanthus niruri L. extract directly loaded onto the adsorbent, and one-step capture of corilagin had been realized. The ethanol aqueous solution of 20%(w/w) was favorable for corilagin elution with recovery and purity of 49.4% and 64.8%, respectively. The adsorption kinetic experiments showed that the pseudo-second order model provided a good fit with the data, but the values of equilibrium adsorption capacity deviated notably, revealing the complexity of the adsorption mechanism. It was considered that the formation of inclusion complex corilagin/β-CD played a significant role on corilagin adsorption and recovery, which was illustrated by the inclusion property investigation. The inclusion complex preferred 1:1 stoichiometry and the association constant was determined as 1.69×103 Lmol−1 at 298K, indicating the β-CD cavity showed excellent affinity to corilagin. Moreover, there was evidence that the crystal pattern of β-CD-PU changed when it adsorbed corilagin by XRD analysis, which indirectly revealed the mechanism of adsorption. These results suggested that β-CD-PU adsorbent was a promising candidate for the recovery and enrichment of corilagin or other polyphenolic natural products from plant materials.


      PubDate: 2016-03-27T14:36:47Z
       
  • Amphiphilic hyperbranched polyglycerol-block-polycaprolactone
           copolymer-grafted nanoparticles with improved encapsulation properties
    • Abstract: Publication date: Available online 8 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Muhammad Ejaz, Alina M. Alb, Scott M. Grayson
      Amphiphilic block copolymer was grafted onto a silica nanoparticle core to template their micelle-like conformation when suspended in water. Such amphiphilic “nanoparticle micelles” will not disaggregate upon dilution, unlike the traditional self-assembled micelles. These nanodispersants were prepared by grafting successive blocks of linear poly(ε-caprolactone) (PCL) and hyperbranched poly(glycerol) (HPG), from functionalized silica nanoparticles (SiO2NPs) using surface-initiated ring-opening polymerization. The swellable hydrophobic PCL inner block enabled the encapsulation of a hydrocarbon payload while the hydrophilic HPG outer block afforded stable dispersions in aqueous media. These nanoparticle-based micelles are proposed as improved dispersants that exhibit stability to high dilution unlike traditional small molecule surfactants. Their capacity for hydrocarbon encapsulation was confirmed by their sequestration of hydrophobic ultraviolet active dyes when dispersed in water. Additional characterization using light scattering-based methodologies combined with ultraviolet spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis experiments confirmed the nanodispersant structure and their “unimolecular micelle-like” behavior.


      PubDate: 2016-03-13T15:55:59Z
       
  • pH-stimulus on-off switching behavior and improved response rate of
           slightly charged poly(N,N-dimethylaminoethyl methacrylate) nano-sized
           composites with incorporated Laponite as crosslinker
    • Abstract: Publication date: Available online 10 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Nermin Orakdogen, Talin Boyaci
      pH-responsive poly(N,N-dimethylaminoethyl methacrylate-co-2-acrylamido-2-methyl-1-propanesulfonic acid) / Laponite (P(DMAEMA-co-AMPS)/Lap) nano-sized composite (NC) hydrogels and cryogels were prepared by in situ free radical polymerization of DMAEMA and AMPS in an aqueous solution with inorganic clay Laponite (Lap) as a crosslinker. pH-dependent swelling properties as well as the elasticity of P(DMAEMA-co-AMPS)/Lap nano-sized composite (NC) hydrogels and cryogels were investigated and the parameters of swelling and diffusion of water in buffer solutions were evaluated as a function of the Lap content. The uniaxial compression measurements exhibited good elastic properties and the nanostructure of NC gels improved the gel strength, while the swelling ratio depended on synergic effects of multifunctional groups. P(DMAEMA-co-AMPS)/Lap NC cryogels exhibit higher elastic modulus than that of the corresponding NC hydrogels over the entire range of the pH. As expected from the protonation of the DMAEMA monomer, P(DMAEMA-co-AMPS)/Lap NC gels showed pH-responsive swelling and were swollen at pH < 7.7 and shrunken at pH > 8.0. This work provides a simple method for fabricating pH-responsive nano-sized composite hydrogels and cryogels with superior mechanical property.
      Graphical abstract image

      PubDate: 2016-03-13T15:55:59Z
       
  • Nanocomposite hydrogel incorporated with polymerizable liquid crystal
           surfactant: Shape transition from layered to honeycomb pore structure and
           thermo/swelling behavior
    • Abstract: Publication date: Available online 12 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Wenjun Gao, Lijuan Xing, Qingsong Zhang, Kun Chen, Pengfei Liu, Li Chen, NingYang, Xiaoyong Zhang, Ke Wang, Yen Wei
      In order to investigate the relationship between nanocomposite hydrogels and polymerizable liquid crystal surfactant, under the physical cross-linking of nanoclay lithium magnesium silicate hydrate (LMSH), a series of poly(NIPAm-LMSH-AAc-Brij-58) nanocomposite hydrogels, based on the copolymerization of polymerizable liquid crystal AAc-Brij-58 synthesized by esterification reaction and N-isopropylacrylamide (NIPAm), were synthesized by in situ free-radical polymerization. The results show that with increasing AAc-Brij-58 concentration from 0 to 1wt%, the particle sizes decrease from approximately 143 to 60nm, and the appearance becomes cruciform or flower type and rod shape, respectively. The obtained nanocomposite hydrogels present thin pore walls and larger pore diameters. With increasing mass ratios of AAc-Brij-58/NIPAm from 0 to 1/15, the maximum swelling ratios exhibit an increasing tendency, the volume phase transition temperatures increase from 32.10 to 33.56°C, and thermal degradation temperature increase from 305 to 340°C.


      PubDate: 2016-03-13T15:55:59Z
       
  • Green anchors: Chelating properties of ATRP-click curcumin-polymer
           conjugates
    • Abstract: Publication date: Available online 10 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Amram Averick, Sukanta Dolai, Ashish Punia, Kamia Punia, Sara R. Guariglia, William L'Amoreaux, Kun-lun Hong, Krishnaswami Raja
      The development of environmentally friendly and biologically benign effective systems to chelate and remove toxic heavy metal ions is of utmost importance. Curcumin, the active ingredient in the spice Turmeric is a known chelator of transition metals. The metal chelation ability of curcumin is severely limited by its hydrophobicity. The efficient synthesis of water soluble curcumin and sugar brush polymer conjugate via atom-transfer radical polymerization (ATRP) and click chemistry is reported here. The polymer conjugate selectively binds and precipitates a range of highly toxic metals that include cadmium, lead, and copper, under physiologically relevant conditions.


      PubDate: 2016-03-13T15:55:59Z
       
  • Shape memory polybenzoxazines based on polyetheramine
    • Abstract: Publication date: Available online 11 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Yanfang Liu, Jinbai Huang, Xuehui Su, Mei Han, Huan Li, Mingtao Run, Hongzan Song, Yonggang Wu
      Five difunctional benzoxazines were synthesized from polyetheramine, phenol, o-allylphenol, o-cresol, p-cresol, m-cresol, and formaldehyde. The substituent groups decrease the ring-opening polymerization to present the ascending order of meta-, para-, and ortho-positions in comparison to the unsubstituted phenol-based benzoxazines. The dynamic mechanical properties of the resultant polybenzoxazines depend on the structure of the starting phenols. The polybenzoxazines exhibit one-way dual-shape memory behavior in response to changes in temperature, and the shape memory effects are evaluated by tensile stress–strain and bending tests with a temperature programme based on glass transition temperature.


      PubDate: 2016-03-13T15:55:59Z
       
  • Synthesis and characterization of 2-hydroxyethyl methacrylate-ethylene
           glycol dimethacrylate polymeric granules intended for selective removal of
           uric acid
    • Abstract: Publication date: Available online 4 March 2016
      Source:Reactive and Functional Polymers
      Author(s): A.P. Leshchinskaya, N.M. Ezhova, O.A. Pisarev
      Suspension polymerization was used in the synthesis of new uric acid-imprinted porous adsorbents based on 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate in the shape of granules. Physico-chemical and adsorption properties of the synthesized adsorbents were studied as well as those of the reference adsorbent (i.e. synthesized in the absence of uric acid). The obtained polymer granules were studied by scanning electron microscopy. Systematic studies of equilibrium and dynamics of uric acid adsorption from aqueous solutions were performed at various temperatures (298K, 310K and 318K). It was established that the amount of introduced template exerts an influence on structural features and sorptive capacity of the synthesized polymers. Molecularly imprinted polymers (MIPs) are capable of extracting uric acid from aqueous solutions with higher sorptive capacity than the reference polymer at various temperatures (298K, 310K and 318K). The uric acid adsorption by the reference polymer (NIP-10) is in good agreement with the Langmuir model, while the uric acid adsorption by imprinted polymers can be better described by the Freundlich model. The MIP-40-10 polymer is capable of adsorbing uric acid with the highest sorptive capacity at three temperatures; the value of imprinting factor is also the highest (IF=4.3, 298K). The studies of adsorption thermodynamics demonstrated that the adsorption process is exothermic in nature.


      PubDate: 2016-03-08T15:38:14Z
       
  • Preparation and characterization of biopolymer nanoparticles based on
           lactoferrin-polysaccharide complexes
    • Abstract: Publication date: Available online 4 March 2016
      Source:Reactive and Functional Polymers
      Author(s): A.V. Il'ina, D.V. Kurek, A.A. Zubareva, M.M. Il'in, N.M. Mestechkina, V.P. Varlamov
      Optimal weight ratios for the preparation of lactoferrin (LF), N-succinyl chitosan (SCh) and galactomannan (GM)-based polyelectrolyte complexes (PEC) were determined. Soluble PEC were obtained using solutions of biopolymers: lactoferrin (2mg/ml), N-succinyl chitosan (8mg/ml) and galactomannan (16mg/ml) in 0.15M NaCl, pH6.5±0.1, under normal conditions at a weight ratio of 1:1 1:2 and 1:3 LF:GM; 1:1, 1:2, 1:3 and 1:4 LF:SCh; 1:3:2 and 1:2:3 LF:SCh:GM. Using the method of heat treatment below the temperature of protein denaturation from the soluble complexes were formed stable biopolymer particles which have size characteristics of 250–400nm, regular spherical shape, a negative zeta potential of 12–17mV and good storage stability. The load of lactoferrin in the particles was 76–87%. Yield of freeze dried particles was 70–80%. The obtained particles could eventually be used for the targeted transport of biologically active substances.


      PubDate: 2016-03-08T15:38:14Z
       
  • Surface characterization and antimicrobial properties of sodium
           deoxycholate-based poly(ester ether)urethane ionomer biomaterials
    • Abstract: Publication date: Available online 4 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Daniela Filip, Doina Macocinschi, Elena Paslaru, Cristina G. Tuchilus, Stelian Vlad
      New sodium deoxycholate-based poly(ester ether)urethane ionomers have been obtained for the development of biomedical materials. Wettability, surface tension parameters, surface morphology, roughness, water sorption and/or desorption properties, antimicrobial efficiency were determined for the obtained polyurethane biomembranes. Contact angle analysis evidenced that the synthesized polyurethane ionomers are hydrophilic due to orientation and amount of ionic bile salt moieties towards surface. The values of interfacial tension demonstrate biocompatible qualities for these polyurethanes. SEM microphotographs show that the resulted morphologies of polyurethane ionomers are different due to the diverse polyether co-soft segments which determine the supramolecular architecture, ionic interactions between bile salt moiety and polyether segments. AFM images evidence lamellar arrangement at the sub-micron scale and the nanophase separated morphology for these polyurethanes. The estimated moisture diffusion coefficients are dependent on a range of moisture transport mechanisms in the porous membranes and the moisture content of the polyurethanes. The monolayer sorption and average pore size values were estimated by applying BET and GAB models. GAB model could not be applied in case of high water uptake polyurethane samples. The synthesized biocidal polyurethanes are effective at inactivation of tested bacteria: S. aureus, S. lutea, E. coli, except P. aeruginosa.


      PubDate: 2016-03-08T15:38:14Z
       
  • Antibacterial nanofilm coatings based on organosilicate and nanoparticles
    • Abstract: Publication date: Available online 5 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Sunghee Hwangbo, Hyejoong Jeong, Jiwoong Heo, Xiangde Lin, Younghak Kim, Minwook Chang, Jinkee Hong
      Super-hydrophilic coatings have been extensively studied because of their diverse applications, especially for anti-bacteria films. Anti-bacterial coatings in biomedical devices need to be durable and bio-compatible, but super-hydrophilic films are commonly very fragile due to a porous structure, which is essential for super-hydrophilic functionality, chemical contamination, and thermal stability. To overcome these drawbacks of anti-bacterial coatings, we introduced polymeric silsesquioxane into the nano-coating, resulting in superior thermal stability and matrix structure based on siloxane groups. Layer-by-layer assembly was used as a multilayer fabrication method to exquisitely control morphology, thickness, and functionality of the nano-coating, and fabricate suitable structures for super-hydrophilic films through simple dipping and washing steps. Antimicrobial and nanoindentation tests were carried out to demonstrate the successful enhancement in the antibacterial and mechanical properties of the nano-coatings.


      PubDate: 2016-03-08T15:38:14Z
       
  • A nitrogen-rich mesoporous polymer for photocatalytic hydrogen evolution
           from water
    • Abstract: Publication date: Available online 5 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Ailan Qu, Xinmei Xu, Yangyu Zhang, Yuyu Li, Wenying Zha, Shengwu Wen, Haolong Xie, Junxian Wang
      Nitrogen-rich hierarchical mesoporous polymers with photocatalytic activity for H2 evolution from water were prepared, which was based on aminal bonds constructed by catalyst-free Schiff-base condensation. The effects of the reaction time, concentration of terephthaldehyde and the mole ratio of aldehyde to amine groups on the structure and properties of polymers were discussed. By tuning reaction conditions, the surface area of these polymers changed from 216.83 to 569.04m2/g. Among all these materials, the polymer with moderate surface area (391.76m2/g), the smallest average pore size (4.27nm) and low intensity peak of photoluminescence showed the highest H2 evolution rate of 18.56μmol·h−1. When loaded with palladium, it exhibited enhanced H2 evolution rate of up to 43.58μmol·h−1. The results demonstrated that the nitrogen-rich porous polymer has a good potential for H2 evolution from water under UV–Vis light irradiation (λ=380–780nm). This study expanded the scope of porous polymers in photocatalysis applications. The outstanding advantages of the polymers presented here include their low price, commercially available starting compounds and the easy method of synthesis. This kind of porous polymer has promise for further applications.
      Graphical abstract image

      PubDate: 2016-03-08T15:38:14Z
       
  • Synthesis and characterization of a high-capacity cationic hydrogel
           adsorbent and its application in the removal of Acid Black 1 from aqueous
           solution
    • Abstract: Publication date: May 2016
      Source:Reactive and Functional Polymers, Volume 102
      Author(s): Run Fang, Wenxuan He, Hanyu Xue, Weijian Chen
      A high-capacity cationic hydrogel adsorbent (CHA) was prepared by polycondensation using triethylenetetramine, acetone and formaldehyde as raw materials. Batch and fixed-bed column experiments were conducted to investigate the adsorption of Acid Black 1 from aqueous solution by CHA. The adsorption mechanism was discussed with respect to its characteristics. Experimental results showed that the adsorption was attributed to a combination of electrostatic attraction and intermolecular interactions between the functional groups of the hydrogel and the dye. The high adsorption capacity of CHA was due to its high cationic charge density and abundant functional groups. Langmuir isotherm fitted well to the equilibrium data and the adsorption process followed pseudo-second-order and intraparticle diffusion kinetic models. The diffusion of dye molecules inside the hydrogel was found to govern the mass transfer process. Good adsorption performance was also observed in the continuous column experiments. The adsorption capacity increased with increasing bed height and decreased with increasing feed flow rate. Overall, the results reported here indicated that CHA could be used as a promising adsorbent for the removal of anionic dyes from wastewater.


      PubDate: 2016-03-08T15:38:14Z
       
  • Investigation of structure property relationships in liquid processible,
           solvent free, thermally stable bismaleimide-triazine (BT) resins
    • Abstract: Publication date: Available online 6 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Alasdair O. Crawford, Gabriel Cavalli, Brendan J. Howlin, Ian Hamerton
      Three cyanate ester monomer or oligomer species: 2,2-bis(4-cyanatophenyl)propane 1, 1-1-bis(4-cyanatophenyl)ethane (2), and the oligomeric phenolic cyanate (Primaset™ PT30) (3), are blended in various ratios with bis(4-maleimidophenyl)methane, (4), to form binary and ternary mixtures (11 in total) and cured, in the absence of catalysts (3Kmin−1 to 150°C+1h; 3Kmin−1 to 200°C+3h), followed by a post cure (3Kmin−1 to 260°C+1h). The use of liquid monomer, (2), offers the possibility of liquid processing in blends containing minority compositions of bismaleimide. Glycidylmethacrylate is explored as a reactive diluent (2.5–10wt%) to linked interpenetrating network polymer structures comprising cyanate ester and bismaleimide components with glass transition temperatures of 267–275°C, depending on composition; the onset of thermo-oxidative degradation ranges from 386 to 397°C. When a binary blend of (2) and (3) (with the former in the minority) is co-cured with (4), an excellent balance of properties is achieved with liquid processing, a T g >400°C and onset of degradation of 425°C in static air. Kinetic analysis of DSC data using Ozawa and Kissinger methods yield activation energies of between 107 and 112kJ/mol for a binary blend of (1)90-(4)10, which is in good agreement with literature. Molecular dynamics simulation of the same blend in cured form gave a simulated glass transition temperature of 250°C that is in very close agreement with empirical DMTA data.


      PubDate: 2016-03-08T15:38:14Z
       
  • Corrosion protection of carbon steel by electrospun film containing
           polyaniline microfibers
    • Abstract: Publication date: Available online 8 March 2016
      Source:Reactive and Functional Polymers
      Author(s): Yunyan Zhao, Zhiming Zhang, Liangmin Yu
      We present here the experimental realization of anticorrosion coating from electrospun conducting polyaniline (PANI)/poly(methyl methacrylate) (PMMA) microfibers film for protecting carbon steel in 3wt% NaCl solution. The preliminary results demonstrate that the carbon steel coated with electrospun PANI/PMMA microfibers film have enhanced anticorrosion performances in comparison with the drop-cast PANI/PMMA film. The superior anticorrosion protection of electrospun PANI/PMMA microfibers film with 25wt% PANI may be due to its extraordinary compact microstructure. The current study may provide a new way of enhancing anticorrosion behaviors of PANI anticorrosion coatings.


      PubDate: 2016-03-08T15:38:14Z
       
  • Phosphazene-cored star polymer bearing redox-active side groups as a
           cathode-active material in Li-ion batteries
    • Abstract: Publication date: Available online 23 February 2016
      Source:Reactive and Functional Polymers
      Author(s): Muhammet Aydin, Mesut Gorur, Faruk Yilmaz
      A new hexa-armed star polymer bearing 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-pending polymer chains emanating from a phosphazene core (P2) was prepared and used as the cathode material in Li-ion battery assembly. The properties of the assembled battery (BP2) were compared with those of BL2 assembled using its linear counterpart (L2). Their spin concentrations investigated via solution electron spin resonance (ESR) measurements were found to be almost the same. The charge/discharge capacities and energy densities of BP2 were considerably higher than those of BL2. However, they exhibited comparable charge/discharge efficiencies and their discharge capacities dropped to similar percentages of their initial values.


      PubDate: 2016-02-25T07:32:07Z
       
 
 
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